James McGrory, chief campaign spokesman for Stronger In said: "There’s always been something fishy about Vote Leave’s arguments, and now we know what it is.

"EU regulations are good for our great British small businesses, from fish smokers to tech start-ups, as they protect their products from being ripped off, and provide free access to a market place of 500 million consumers.

"Pulling out of the EU’s Single Market, as Vote Leave want us to do, would be a hammer blow that could hit our economy to the tune of £4,300 a year for the average household.

"Don’t believe Vote Leave’s fantasy economics – Britain is stronger in Europe, while leaving would be a leap in the dark that would damage our small businesses."

Speaking at the Vote Leave event, Boris Johnson claimed that around 300,000 new jobs would be created if Britain threw off the “shackles” of the EU.

John Stillwell/PA Wire
Priti Patel, former England footballer Sol Campbell, Boris Johnson and Michael Gove during at the rally

According to the Press Association, he said: "If we Vote Leave we will be able to forge bold new trade deals with growing economies around the world. These are deals that the EU has tried and failed to achieve due to protectionist forces in Europe.

"After we liberate ourselves from the shackles of Brussels we will be able to create hundreds of thousands of new jobs right across the UK.

"Predictably the gloomsters want to do down Britain - they claim we are not strong enough to stand on our own two feet. What total tosh. There is a huge world of opportunity and prosperity out there if we take this opportunity to take back control."